Induced and forced draft apparatus



New. :13 H923.

, E. PRAT INDUCED AND FORCED DRAFT APPARATUS Filed April 2 1920 11 .5

A mrmy Patented Nov. 13, 1923.

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EMILE PHAT, 0F PARIS, FRANCE, ASSIGNOR T0 sOGIE'rE DES cHEMINEEs LoUIs Peace A TIRAGE INDUIT,

OF PARIS, FRANCE.

INDUCED AND FOB-CED DRAFT APPARATUS.

Application filed April 2,

- To (17/ 'HIIOHZ it may concern:

lie it known that I, EMILE Pna'r, citizen of the French Republic, residing at. Paris, France. (34: Rue de Miromesnil, have invented certain new and useful Improvement in induced and Forced Draft. Apparatus, of which the following is a specification.

In certain induced-draft installations for furnaces. a fan delivers a portion of the combustion gases from the firebox into the chimney in order to effect the aspiration of the remainder of thegases. According to the present invention. in order to simplify the installation, two fans are replaced by a single rotor divided into two approximately symmetrical parts one of which is traversed by a portion of the combustion gases from a furnace and produces draft by ejector action in the chimney, while the other supplies the draft air to the grate, either direct to the underside of the grate or elsewhere, as, for instance, to an air-heater.

According to the invention, the heating of the blast air can be effected by means of a shell. wholly or partially surrounding the metal chimney, the air being aspirated by the fan, into the space between the shell and the chimney, so as to recover a portion of the heat contained in the flue gases.

In the accompanying drawing which illus trates, by way of example, several methods of carrying out the invention, Figs. 1 and 2 are respectively a vertical section and a plan of an induced-draft chimney fitted with the airheating device, and comprising a rotor or fan with double acting sections arranged inside the chimney. Figs. 3 and 4 are respectively a sectional elevation and a plan of the sectional rotor or fan provided with blade rims, the rotor or fan being situated outside the chimney.

Fig. 5 is a vertical sectional view on the line 55 of Fig. 1;

Fig. 6 is a horizontal sectional view on the line 6-6 of Fig. 1.

1 is the flue through which the gases pass on the way to the chimney; 2 is the sheet iron chimney; 3 is the chimney shell; 1 are braces connecting the shell with the chimney; 5 is the cold-air intake between the chimney 2 and the shell 3; 6 is the air intake of the rotor or fan section 7, which delivers the partly heated air, by way of the passage Sfinto the air heater 9, and thence to the tire-grate S through the passage 10;

1920. Serial N0. 370.862.

11 is the other rotor Or fan section, of which 14: is the intake and 15 the delivery nozzle. The sectional rotor or fan 711 is driven by the motor 13; the shaft therefor being indicated at 12.

The combination of artificial draft and air heating operates in the following 1nanner:-The products of combustion coming from the flue 1 are partially aspirated by the fan section 11 and delivered through the nozzle 15 into the chimney, which aspirates the remainder of the gases, whilst the cold external air entering the annular space 5 is heated between the chimney 2 and the wall 3, and is delivered by the fan section 7 to the grate by way of the passages 8 and 10 and heater 9.

The air heater may be constructed in accordance with the disclosure in my co-pending application Serial No. 4L20A60, tiled October 2). 1920, although any known type of heater may be employed, as this does not form part of the present application. The air to be heated passes through the spaces 22 between plates 20 (Figs. 5 and (S) from top to bottom, flows around the partitions 23,-thence upwardly to the passage 10 lead-- ing to the grate. The combustion from the furnace pass horizontally through the spaces 21 between the plates 20 and pass partially to the intake 14 of the fan section 11 and partially around the fan directly up the chimney 2.

Figs. 3 and a show in greater detail, the internal arrangement of the rotor or fan. including the two stationary spiral chambers 17 and 18 therefoi which may be situated outside the chimney 2; 16 represents the rimmed blades of the. rotating fan sections provided in turn with the two intakes, of which 6 is the intake of cold or partly heated air, and list, the intake for the prod nets of combustion; 19 is the partition separating the two spiral chambers 17 and 18, the one discharging the air, by way of the passage 8, into the air heater such as indicated at 9 in Fig. 1. and the other discharging the flue gases towards the nozzle 15 in the chimney as in Fig. 1.

The invention applies equally to the case in which the chimney draft is produced by an air blast instead of by the gases.

hat I claim is:

1. An apparatus for the production of draft in "furnaces by simultaneous induction and blowing, comprising a chimney flue, a casing arranged within the chimney fine and divided into two compartments having independent central inlets and peripheral outlets, a rotatable shaft in said casing, bearings supporting said shaft at each end on opposite sides of the flue, fan sections carried by the shaft and operating in the respective compartments, a delivery nozzle on one of the sections opening into the chimney at the axes thereof, said fan sections communicating with the interior of the chimney flue and being traversed by only a portion of the combustion gases from the furnace and adapted to produce a draft by ejector action in the chimney, the other fan section having its inlet in communication with the atmosphere and adapted to direct an air blast to the grate of the furnace.

2. An apparatus for the production of draft in furnaces by simultaneous induction and blowing, comprising a chimney flue, a casing arranged within the flue and divided into two compartments having central inlet and peripheral outlets,a rotatable shaft in the casing, bearings supporting said shaftat each end on opposite sides of the chimney flue, fan sections carried by the shaft and operating in the compartments, a delivery nozzle for one of the sections opening into the chimney flue at the axes of the latter, said fan section having its inlet into communication withthe interior of the chimney flue and'being traversed by only a portion of the combustion gases from the furnace and adapted to produce a draft by ejector action in the chimney flue, a conduit connected with the outlet for the other fan sec tiou, air heating means associated with the chimney flue and communicating with the air inlet of the second mentioned fan section whereby to heat the air preliminary to its admission to the second mentioned fan section, and means associated with said conduit and said flue for further heating said air, subsequent to its discharge from thesecond mentioned fan section.

EMILE PRAT. 

